Device and method for identifying plastic

ABSTRACT

A plastic identifying apparatus of the present invention is provided with a sampling unit ( 2 ) that samples a test piece ( 1 ) from an item to be identified that contains plastic; an identifying unit ( 3 ) provided with a detection unit ( 4 ) that identifies a type of plastic contained in the test piece ( 1 ); and a supply unit ( 5 ) that supplies the test piece ( 1 ) from the sampling unit ( 2 ) to the detection unit ( 4 ). With this plastic identifying apparatus, it is possible to realize a plastic identifying method of the present invention, and to identify the types of plastics contained in items to be identified with good accuracy, and continuously, regardless of the size of the items.

TECHNICAL FIELD

The present invention relates to plastic identifying apparatuses andplastic identifying methods.

BACKGROUND ART

Conventionally, waste plastics discarded from households and so on aredisposed of by such means as incineration and burying. However,incineration and burying have been increasingly accompanied by anenvironmental impact, shortages of landfill areas, and other socialproblems. In recent years, work has progressed concerning thesorting/recovering and recycling of waste plastics, and for thesereasons, identifying the types of waste plastics has been seen asextremely important. Also, in order to achieve processing for as muchwaste plastics as possible, there is a need for such identification tobe performed with good accuracy and continuously.

Conventionally, methods of identifying types of waste plastics includemethods that involve comparison of specific gravities, and methods usingfluorescent X-rays or near-infrared light. However, it has been verydifficult up until now to identify plastic types with good accuracy andcontinuously. For example, when there are almost no differences betweenthe specific gravities of plastics, it is very difficult to use methodsthat involve weight comparisons. And for identification methods usingnear-infrared light, it is difficult to identify plastics when, forexample, they are dark-colored plastics. However, for householdelectrical appliances discarded from households, for example, televisionreceivers, there are many dark-colored waste plastics, and there areadditional difficulties in identifying these with good accuracy becauseof such factors as surface coatings on the plastics, surface degradationdue to long use, smearing of grime and other dirt, and the flameretardants contained within these products. It should be noted thatthroughout this specification, near-infrared light refers to the lightwhose wave number is in the range approximately from 4,000 cm⁻¹ to13,000 cm⁻¹.

Furthermore, conventionally, identification is performed directly forhousehold electrical appliances such as, for example, televisionreceiver chassis. However, in recent years, the size of televisionreceivers has been increasing, and the sizes of the discarded chassisalso have been increasing. In terms of the tasks and labor required, itis difficult to directly identify these types of large-sized plasticproducts. Also, they make it difficult to introduce continuous lines atrecycling plants and inevitably involve increasing the size of theequipment required for identification.

DISCLOSURE OF INVENTION

In view of such conditions, it is an object of the present invention toprovide a plastic identifying apparatus and plastic identifying methodthat enable plastic types to be identified accurately and continuously,regardless of the size of the plastic-containing items to be identified.

To achieve this object, a plastic identifying apparatus of the presentinvention is provided with a sampling unit that samples a test piece ofthe item to be identified that contains plastic, and an identifying unitprovided with a detection unit that identifies types of plastics,including the above-mentioned test piece, as well as a supply unit tosupply the test piece from the sampling unit to the detection unit.

The detection unit of the plastic identifying apparatus is also capableof irradiating infrared light of a predetermined wave number onto thetest piece, and detecting the intensity of the infrared light that istotally reflected by the test pieces.

The plastic identifying apparatus also can be provided with a pressingdevice that brings the test piece into contact with the detection unit.

The plastic identifying apparatus also can be provided with a cleaningunit that cleans the detection unit.

The sampling unit of the plastic identifying apparatus also can beprovided with a means for punching a test piece from the item to beidentified.

It is possible for the punching means of the plastic identifyingapparatus to be a punch press.

The plastic identifying apparatus also can be provided with a chuckingunit that holds the test piece sampled by the sampling unit.

The chucking unit of the plastic identifying apparatus also can beprovided with a rotation unit that rotates the test piece around ahorizontal rotational axis while the chucking unit holds the test piece.

The test piece of the plastic identifying apparatus can be in the formof an approximate “T”, shape, or in the form of an approximate “L”shape.

The detection unit of the plastic identifying apparatus can performidentification for at least two surfaces of the test piece.

The plastic identifying apparatus also can be provided with a cleaningunit that surface cleans the test piece.

The plastic identifying apparatus also can be provided with a pressingunit that presses against a surface of the test piece.

The plastic identifying apparatus also can be provided with a polishingunit that provides a surface of the test piece with uniformity.

The plastic identifying method of the present invention includes:

-   (i) a step of sampling a test piece from an item to be identified    that contain plastics,-   (ii) a step of supplying the sampled test piece to a detection unit    for identification of the type of plastic contained in the test    piece, and-   (iii) a step of identifying the type of plastic contained in the    test piece with the detection unit.

In the plastic identifying method, step (ii) can contain a step ofirradiating infrared light of a predetermined wave number onto the itemto be identified, and the intensity of the infrared light totallyreflected by these items is detected.

In the plastic identifying method, step (iii) can be performed bybringing the test piece into contact with the detection unit.

In the plastic identifying method, step (iii) can be performed bybringing the test piece into contact with the detection unit afterletting the test piece become stationary above the detection unit.

In the plastic identifying method, step iii) can be performed for atleast two surfaces of the test piece.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic drawing showing an example of a plasticidentifying apparatus of the present invention.

FIG. 2 is a cross-sectional view that shows an example of a detectionunit in a plastic identifying apparatus of the present invention.

FIG. 3 is a schematic drawing showing an example of a cleaning unitcleaning a detection unit in a plastic identifying apparatus of thepresent invention.

FIGS. 4A and 4B are schematic drawings showing an operational example ofa chucking unit in a plastic identifying apparatus of the presentinvention.

FIG. 5 is a schematic drawing showing an examplary shape of a test piecein the present invention.

FIG. 6 is a schematic drawing showing another examplary shape of a testpiece in the present invention.

FIG. 7 is a cross-sectional view that shows an example of therelationship between a test piece and a detection unit.

FIG. 8 is a schematic drawing showing an example of a cleaning unitcleaning the surface of a test piece in a plastic identifying apparatusof the present invention.

FIG. 9 is a schematic drawing showing an example of a pressing unitpressing against the surface of a test piece in a plastic identifyingapparatus of the present invention.

FIG. 10 is a cross-sectional view of an example of a test piece that hasburrs.

FIG. 11 is a cross-sectional view that shows an example of therelationship between a test piece and a detection unit.

FIG. 12 is a cross-sectional view that shows an operational example of achucking unit in the present invention.

FIG. 13 is a cross-sectional view that shows an example of therelationship between a test piece and a detection unit.

FIG. 14 is a cross-sectional view that shows an example of therelationship between a test piece and a detection unit.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the accompanying drawings, the following is an explanationof embodiments of the present invention. It should be noted that in thefollowing embodiments, same components are referred to by the samereference numerals, and duplicate explanations are sometimes omitted.

Embodiment 1

FIG. 1 is a schematic drawing of one example of a plastic identifyingapparatus of the present invention.

The example shown in FIG. 1 includes a sampling unit 2, which samples atest piece 1 from items 51 to be identified that contain plastic; anidentifying unit 3, which is equipped with a detection unit 4 foridentifying the types of plastics contained in the sampled test pieces1; and a supply unit 5, which supplies the sampled test piece 1 from thesampling unit 2 to the detection unit 4.

Instead of directly identifying the items to be identified as inconventional methods, this plastic identifying apparatus samples a testpiece and identifies the types of plastics contained in the sampled testpiece. Therefore, it can carry out identification easily, even for largesized items to be identified, and the overall size of the apparatus canbe very compact. Also, because such factors as the size and shape of thetest piece can be optimized to suit the detection unit, accurate andconsistent identification can be achieved regardless of the shape of theobjects to be identified, and it is also suitable for continuousidentification processes.

Note that, although FIG. 1 shows the back cover of a television receiveras the item 51 to be identified, there is no particular limitation tothe shape, material, etc., of items to be identified as long as theycontain plastic. Further, in the example shown in FIG. 1, the entireplastic identifying apparatus is positioned on a bench 52, however, thebench 52 is in no way a definite requirement. The plastic identifyingapparatus of the present invention can be positioned at any location.Also, the respective relative positions of the sampling unit 2, theidentifying unit 3, and the supply unit 5 can be freely arranged. Asshown in the example of FIG. 1, when the sampling unit 2 and theidentifying unit 3 are adjacent, the apparatus can be very compact, andthe speed of the identification process can be enhanced.

There is no particular limitation on the identifying unit 3, as long asit is provided with a detection unit 4 that can identify the types ofplastics contained in the test piece 1. For example, as shown in FIG. 1,it may be an arrangement with the detection unit 4 and a control unit 6that controls the detection unit 4.

There is no particular limitation on the detection unit 4, as long as itcan identify the plastic types contained in the test piece 1. Forexample, it may be a detection unit that utilizes methods using ordinaryplastic analysis. These methods may be, for example, Ramanspectrophotometry or infrared spectroscopy, etc.

The detection unit 4 may be a detection unit that uses a method in whichinfrared light of a predetermined wave number is irradiated onto thetest piece 1 and the intensity of the infrared light that is totallyreflected by the test piece 1 is detected (throughout thisspecification, this method is referred to as “infrared total reflectionmeasurement method”). When using this method, even when the test piecescontain dark-colored plastics, or contain flame retardants, the types ofplastics contained in the test pieces can be detected accurately. Itshould be noted that the above-mentioned predetermined infrared lightwave number (also referred to below as “infrared light”) is in therange, for example, of 400 cm⁻¹ to 4,000 cm⁻¹ (which puts this lightinto the category of ordinary mid infrared light).

When identifying the type of plastic contained in the test piece 1,infrared light can be irradiated on the test piece 1 while varying thewave number of the infrared light, and the intensity (or absorbance) ofthe totally reflected infrared light for each wave number can bedetected. It is also possible to detect the intensity (or absorbance) ofthe totally reflected infrared light using Fourier transform infrared(FT-IR) spectroscopy. For example, wavelength-intensity distributionsfor predetermined plastics may be recorded in advance in a control unit6, and by comparing them with the wavelength-intensity distributionobtained by the above-mentioned detection, the plastic types containedin the test piece 1 can be identified easily.

An example of a detection unit 4 that uses the above-mentioned infraredtotal reflectance measurement method is shown in FIG. 2. In the exampleshown in FIG. 2, the detection unit 4 is provided with a prism 7. Theprism 7 irradiates infrared light 8 of a predetermined wave number froma detection aperture 9 onto the test piece 1. The incident infraredlight 8 is totally reflected by the test piece 1, and after passingthrough the prism 7 again, its intensity is detected. Also, although notindicated, the detection unit 4 is provided with an infrared lightsource for outputting infrared light 8 and a detection device formeasuring the intensity of the infrared light 8 that is totallyreflected by the test piece 1. It should be noted that FIG. 2 is across-sectional view, but in order to make the drawing easier to view,hatching has been omitted. The same applies to other cross-sectionalviews hereinafter, except for FIG. 10.

In the plastic identifying apparatus of the present invention, it isalso possible that the detection unit identifies at least two surfacesof the test pieces. For example, after the detection unit detects thewavelength-intensity distribution for one surface of the test piece (forexample, the surface corresponding to the front surface of the item tobe identified), the test piece could be rotated so that thewavelength-intensity distribution of a surface different from the onejust measured (for example, a surface that is first exposed duringsampling) could be measured. Even when there is a coating on the surfaceof the item to be identified, or if the surface is degraded, because atleast two surfaces of the test pieces sampled from the items to beidentified are measured, the types of plastic contained in the testpieces can be identified more accurately. In order for the detectionunit to measure at least two surfaces of the test pieces, the supplyunit can be provided with, for example, a chucking unit, which will beexplained later.

In the plastic identifying apparatus of the present invention, apressing device can be provided to bring the test piece into contactwith the detection unit. For example, as shown in FIG. 1, theidentifying unit 3 can be provided with a pressing device 10. In thedetection unit 4, as shown in FIG. 2, when identifying the plastic typescontained in the test piece 1, if the pressing device 10 brings the testpiece 1 into contact with the detection unit 4 (or in the example inFIG. 2, with the detection aperture 9 at which the infrared light isincident on the test piece 1), it becomes possible to identify theplastic types contained in the test piece 1 very reliably. It is veryeffective if, as shown in FIG. 2, the detection unit uses the infraredlight total reflectance measurement method. As long as the test piece isbrought into contact with the detection unit, there is no particularlimitation to the structure, materials, or shape of the pressing device.For example, metals or glass could be used for the materials of thepressing device.

In the plastic identifying apparatus of the present invention, thedetection unit may be provided further with a cleaning unit. FIG. 3shows an example of this.

The cleaning unit 11 shown in FIG. 3 is provided with a rotatable brush12. When cleaning the detection unit 4, the brush 12 can be rotatedafter being brought into contact with the detection unit 4. The area inwhich cleaning is performed in the detection unit 4 can be freelyadjusted, as required. For example, as shown in FIG. 3, if the brush 12is rotated after being brought into contact with the detection aperture9, it is possible to clean the vicinity of the detection aperture 9 inthe detection unit 4. Further, when not performing cleaning, thecleaning unit 11 can be made to stand by at a predetermined position soas not to interfere with the identification of test pieces. It is alsopossible to provide the identification unit 3 with a cleaning unit 11.

The timing for the cleaning of the detection unit 4 by the cleaning unit11 can be before or after, or before and after the measurement of thetest piece. Further, the cleaning method is not limited to the method ofrotating a brush as shown in FIG. 3. For example, it is also possible toclean the detection unit by sliding a brush left and right. Also,instead of a brush, cleaning can also be performed by blowing air ontothe detection unit. As long as the detection unit 4 can be cleaned,there is no particular limitation to the structure, materials, or shapeof the cleaning unit. For example, a cloth or sponge could be used asthe material for the brush 12 of the cleaning unit 11 shown in FIG. 3.

Identification of the test pieces can be affected adversely by dustadhering to the detection unit, or by debris or the like adhering to thetest pieces. When a cleaning unit for cleaning the detection unit isfurther provided, it can remove the dirt, etc., that adheres to thedetection unit. And for this reason, the types of plastics contained inthe test pieces can be identified with greater accuracy and consistency.

As for the sampling unit of the plastic identifying apparatus of thepresent invention, as long as it can sample test pieces from the itemsto be identified, there is no particular limitation to its structure,etc. For example, it may be provided with a means for punching testpieces from the items to be identified. There are various conceivablemethods for sampling test pieces from the items to be identified, suchas cutting, etc., but using a punching method allows test pieces to besampled very easily.

As for the above-mentioned punching means, a punch press, for example,or similar may be used. In the example shown in FIG. 1, the samplingunit 2 is fitted with a punch press 13.

As for the supply unit in the plastic identifying apparatus of thepresent invention, as long as it can supply test pieces from thesampling unit to the detection unit, there is no particular limitationto its structure etc. For example, as shown in FIG. 1, the supply unit 5may be provided with a chucking unit 14 to hold the test piece 1 thathas been sampled by the sampling unit 2. If the test piece 1 is suppliedto the detection unit 4 by the chucking unit 14, the type of plasticcontained in the test piece 1 can be identified with accuracy andconsistency.

When the supply unit is provided with a chucking unit, the chucking unitcan hold the test piece at the sampling unit and supply it as is to thedetection unit. Furthermore, as shown in the example in FIG. 1, thesupply unit 5 can be provided with a test piece transport unit 15 (fortransporting the test piece 1 from the sampling unit 2 to the chuckingunit 14) and the chucking unit 14.

In the example shown in FIG. 1, the test piece 1 punched by the punchpress 13 drops as it is and is then stored by a test piece holder thatis positioned inside the test piece transport unit 15. The test pieceholder that stores the test piece 1 moves along a guide rail inside thetest piece transport unit 15, and approaches the vicinity of thechucking unit 14, thus transporting the test piece 1 to the chuckingunit 14. At that stage, if the chucking unit 14 is not holding anything,the test piece 1 can be supplied as is to the detection unit 4 by thechucking unit 14. If the chucking unit 14 is holding another test piece,the test piece 1 being transported by the test piece transport unit 15can be made to stand by where it is, then supplied to the detection unit4 after waiting for the chucking unit 14 to become free.

In this case, while one test piece is being identified at the detectionunit 4, another test piece can be sampled and transported to thevicinity of the chucking unit 14 by the test piece transport unit 15.For this reason, the steps of sampling and transporting the test piecescan be performed in parallel to the steps of supplying the transportedtest pieces to the detection unit and identifying them, thus affordingimproved identification capabilities. And for this reason, it becomeseasy to implement continuous identification operations.

There is no particular limitation to the structure, etc., of the testpiece transport unit 15, as long as it can transport the test pieces 1from the sampling unit 2 to the chucking unit 14. For example, it couldbe configured as a test piece transport unit using such items as belts,slide rails, or air-driven components.

Furthermore, the chucking unit may be provided with a rotation unit thatrotates test pieces around a horizontal rotational axis. In this case,at least two surfaces of the test pieces can be identified very easily.An example of such a chucking unit is shown in FIGS. 4A and 4B.

In the examples shown in FIGS. 4A and 4B, the chucking unit 14 isequipped with a rotation unit 16 and a chuck 17. While a test piece 18is held by the chuck 17 with the rotation unit 16, rotation around ahorizontal rotational axis (a horizontal direction perpendicular to thedirection of axis A in FIG. 4A) is achieved (that is, the test piece 18can rotate around a horizontal axis). As long as the rotation unit 16can rotate the test piece 18, which is held by the chuck 17, in theabove-mentioned manner, there is no particular limitation to itsstructure, etc. Further, as long as the chuck 17 can hold the test piece18, there is no particular limitation to its structure, etc.

The chuck 17 shown in FIGS. 4A and 4B can be moved vertically (directionof axis A in FIG. 4A) in order to position the test piece 18 on thedetection unit 4. It is also possible to move the entire chucking unit14 up and down by moving the rotation unit 16 up and down. In this case,as long as the rotation unit 16 can rotate the test piece 18 held by thechuck 17 in the above-mentioned manner, and as long as the rotation unit16 itself can move up and down, there is no particular limitation to itsstructure.

FIGS. 4A and 4B will be used to explain the process by whichidentification is performed for at least two surfaces of the test piece18.

First, as shown in FIG. 4A, the test piece 18, which was sampled by thesampling unit, is held by the chuck 17 and positioned above thedetection unit 4. The test piece 18 is in the approximate shape of a“T,” and test pieces such as this can be obtained, for example, by usinga die provided with a “T” shape to punch press the items to beidentified.

After the test piece 18 is positioned, the identification for the typeof plastic contained in one of its surfaces is performed by thedetection unit 4. At this time, the test piece 18 can be brought intocontact with the detection unit 4 by the above-mentioned pressingdevice. The operation of the chuck 17 when a pressing device is usedwill be discussed later.

After this identification, the chuck 17, which is holding the test piece18, is raised once in the A-axis direction shown in FIG. 4A. Then, asshown in FIG. 4B, the chuck 17 (that is, the test piece 18), is rotatedby the rotation unit 16 at least 90° in the direction indicated by arrowB. After this rotation, the chuck 17 is lowered again in the A-axisdirection, and a surface of the test piece 18 that is different from theprevious surface is positioned above the detection unit 4, so that thisdifferent surface can be identified for the type of plastic containedtherein. In this way, identification for at least two surfaces of thetest piece 18 can be performed very easily. Note that the angle ofrotation for the test piece is not limited to the above-mentioned 90°,but can be freely adjusted to suit the shape of the test piece.

There is no particular limitation to the shape of the test pieces. Forexample, the shape can be that of the “T” shaped test piece 18 shown inFIGS. 4A and 4B, or the “L” shaped test piece 19 shown in FIG. 5. Inthese circumstances, because there is no interference between the chuck17 and the upper surface of the detection unit 4 for the series of stepsdescribed above of identifying at least two of the surfaces of the testpiece, this series of steps can be performed very smoothly.

For example, when the test piece 20 has an approximate rectangular shapeas shown in FIG. 6, there is the possibility of interference occurringbetween the chuck 17 and the upper surface of the detection unit 4during the above-mentioned series of steps. For example, after thedetection unit 4 has identified one surface of the test piece 20, thechuck 17, which is holding the test piece 20, is raised once and thenthe chuck 17 (that is, the test piece 20) is rotated at least 90°, then,after this rotation, when attempting to position the test piece 20 againover the detection unit 4, if left in this manner there will beinterference between the chuck 17 and the upper surface of the detectionunit 4 as shown in FIG. 7 (the shaded area in FIG. 7 is the area ofinterference). This interference can be resolved by either rotating thetest piece by 180°, or by horizontally changing the grip of the chuck 17on the test piece when repositioning the test piece 20 after rotation,thereby allowing measurement of the test piece 20 without problem.However, when the test piece is in either an approximate “T” shape or anapproximate “L” shape, the test piece can be repositioned without anychange of grip on the test piece. For this reason, it is possible toeliminate chucking errors that could cause the test piece to come looseand fall, or the like, and identification for the plastic typescontained in the test piece can be performed with greater consistency.

The plastic identifying apparatus of the present invention can beprovided further with a cleaning unit for cleaning the surfaces of thetest pieces. FIG. 8 shows an example of this.

In the example shown in FIG. 8, a cleaning unit 21 is provided with arotatable brush 22. To clean the surface of the test piece 1, the brush22 is lowered until it contacts the test piece 1, and after contact hasbeen made, the brush 22 can be rotated. Note that, as long as it canperform surface cleaning for the test piece 1, there is no particularlimitation to the structure, materials, or form of the cleaning unit 21.For example, the material used for the brush 22 shown in FIG. 8 may becloth, sponge, or similar.

The cleaning unit 21 can be positioned in any desired location, from thesampling unit 2 shown in FIG. 1 to the detection unit 4. For example, itcan be positioned at the test piece transport unit 15. In this case, thesurface of the test piece 1 can be cleaned before the test piece 1sampled by the sampling unit 2 is transported to the chucking unit 14.Also, this cleaning can be performed by temporarily stopping thetransport of the test piece 1 and bringing the brush 22 into contactwith the stopped test piece 1 as shown in FIG. 8. Also, the position ofthe brush 22 can be determined in advance and cleaning can be performedby bringing the brush 22 into contact during the transport of the testpiece 1. Note that, in addition to performing cleaning by brush rotationas shown in FIG. 8, cleaning can be performed by having the brush slideleft and right.

Foreign matter, such as dirt that adheres to the surface of the testpieces, can be removed by providing a cleaning unit such as this, thusallowing types of plastics contained in the test pieces to be identifiedwith greater accuracy and consistency.

The plastic identifying apparatus of the present invention can beprovided further with a pressing unit to press the surface of the testpieces. An example of this is shown in FIG. 9.

By pressing the surface of the test piece 1 with a pressing unit 23 asshown in FIG. 9, the surfaces of test piece 1 can be provided withuniformity. As long as it can provide uniformity for the surfaces oftest piece 1, there is no particular limitation to the structure,materials or form of the pressing unit 23. For example, metals, glass,or the like may be used for the surface of the pressing unit 23 thatcontacts the test piece 1.

The pressing unit 23 can be positioned in any desired location from thesampling unit 2 shown in FIG. 1 to the detection unit 4. For example, itcan be positioned at the test piece transport unit 15. In this case, thesurfaces of the test pieces 1 can be pressed and provided withuniformity before the test piece 1 sampled by the sampling unit 2 istransported to the chucking unit 14.

The following is an explanation of “surface uniformity.” As shown inFIG. 10, depending on the sampling method, there may be a burr 25 on theedges of test piece 1 sampled by the sampling unit. When burrs such asthese are present on the test pieces, it is possible that, as shown inFIG. 11, when the test piece is to be positioned over the detection unitfor identification, it is not possible to bring the test piece 1 intocontact with the detection unit 4 due to the burr 25. This is also thesame even when a pressing device 9 presses the test piece 1 to thedetection unit 4. When the test piece 1 cannot be brought into contactwith the detection unit 4, there is the possibility that the accuracy ofidentifying the plastic types contained in the test pieces 1 will beaffected adversely. For this reason, it is preferable that the presenceof protruding portions such as burrs on the test pieces is minimized,and that the surfaces are as uniform as possible.

When the plastic identifying apparatus is provided with a pressing unit23 as shown in FIG. 9, greater accuracy and consistency can be achievedin the identification of the plastic types contained in the test pieces,because the presence of burrs on the test pieces can be minimized. Notethat in the example of the detection unit 4 shown in FIG. 11, althoughthe detection unit there uses the infrared total reflectance measurementmethod shown in FIG. 2, the same applies even if the method used is adifferent method.

Further, the plastic identifying apparatus of the present invention alsocan be provided with polishing unit to provide uniformity for thesurfaces of the test pieces. Similar to the above-mentioned situation inwhich a pressing unit is provided, the identification of the plastictypes contained in the test pieces can be performed with greateraccuracy and consistency, because the presence of burrs on the testpieces can be minimized.

Furthermore, after identifying the plastic types contained in testpieces using the plastic identifying apparatus of the present invention,the items to be identified, which have had test pieces sampled, can besorted based on those results. For that purpose, for example, inaddition to the plastic identifying method of the present invention,object sorting apparatuses, or a control system that links plasticidentifying apparatuses with object sorting apparatuses can be provided.In this case, the following procedure, for example, can be performed.

First, test pieces are sampled from the items to be identified by theplastic identifying apparatus. Next, the plastic types contained in thetest pieces (that is, the plastic types contained in the items to beidentified) are identified by the plastic identifying apparatus.Meanwhile, items to be identified are transported to an object sortingapparatus. The results of the above-described identification process aretransmitted to the object sorting apparatus via a control system, andthe items are sorted based on these results. Note that, as long as theobject sorting apparatus can sort identified objects, there is noparticular limitation to its structure, etc.

Embodiment 2

One example of an embodiment of the plastic identifying method of thepresent invention will be explained using the example of a plasticidentifying apparatus shown in FIG. 1.

The plastic identifying method of the present invention includes, (i) astep of sampling the test piece 1 from the item 51 to be identified thatcontains plastic, (ii) a step of supplying the sampled test piece 1 to adetection unit 4 for identification of the plastic types contained inthe test pieces, and (iii) a step of identifying the plastic typescontained in the test piece 1 with the detection unit 4.

Instead of directly identifying the items to be identified as inconventional methods, in this plastic identifying method, test piecesare sampled and these test pieces then are identified. Therefore,identification can be performed easily, even for large objects to beidentified, and the overall equipment size can be made very compact.Also, because such factors as the size and shape of the test pieces canbe optimized to suit the detection unit regardless of the shape of theobjects to be identified, very accurate and stable identification can beperformed, and it is possible to anticipate continuous identificationprocesses.

For sampling the test pieces 1 from the items 51 to be identified thatcontain plastics, as shown in FIG. 1, the items 51 to be identified canbe set in the sampling unit 2 and the test pieces 1 can be punched outby the punch press 13. Also, when supplying the sampled test pieces 1 tothe detection unit 4, the test pieces 1 are first transported by thetest piece transport unit 15 from the sampling unit 2 to the chuckingunit 14, then the transported test pieces 1 can be supplied to thedetection unit 4 by the chucking unit 14. Note that this series of stepscan be automated.

In the plastic identifying method of the present invention, foridentification by the detection unit of the plastic types contained inthe test piece, infrared light of a predetermined wave number can beirradiated onto the item to be identified, and the intensity of theinfrared light that is totally reflected by this item can be detected.When using this method (infrared total reflectance measurement method),the type of plastic contained in the test piece can be identified veryaccurately, even in cases when the test piece includes dark-coloredplastic, or in cases when the test piece contains flame retardants. Notethat the above-mentioned predetermined infrared light wave number is ina range, for example, from 400 cm⁻¹ to 4,000 cm⁻¹. In order to implementthis method, it is possible to use, for example, the example detectionunit shown in FIG. 2, which uses an infrared total reflectancemeasurement method.

In the plastic identifying method of the present invention, when thedetection unit is identifying the plastic types contained in the testpiece, the test piece can be brought into contact with the detectionunit. If the test piece is brought into contact with the detection unit,the type of plastic contained in the test piece can be identified withgreater certainty. In particular, a detection unit using theabove-mentioned infrared total reflectance measurement method isparticularly effective. In order to bring the test piece into contactwith the detection unit, it is possible to use, as shown in FIG. 1 forexample, a pressing device 10.

Furthermore, when bringing a test piece into contact with the detectionunit, the test piece can be brought into contact with the detection unitafter letting the test piece become stationary above the detection unit.For example, when using the pressing device 10 shown in FIG. 1 as amethod for bringing these into contact, it is possible to use a chuckingunit 14, the operation of which is explained in an example below(explained using FIG. 12). Note that the chucking unit is provided witha chuck that holds the test piece, but in order to simplify theexplanation, only the chuck is shown in FIG. 12. Also, “stationary” asused in this specification refers to a placement state that isindependent of and not supported by any means. No consideration is givento the duration of this state.

As shown in FIG. 12, the test piece 1 is first positioned over thedetection unit 4 by a chuck 17, after which the chuck 17 is opened(moved in the directions indicated by the X arrows in FIG. 12) and thetest piece 1 is released and allowed to become stationary. Next, thepressing device 10 is moved in the direction indicated by the Y arrow inFIG. 12, and the test piece 1 is brought into contact with the detectionunit 4. While kept in contact in this manner, identification isperformed for the plastic types contained in the test piece 1. Afterthis identification is finished, the pressing device 10 is separatedfrom the test piece 1 and then the test piece 1 is again held by thechuck 17, so that the test piece 1 can be transported from the detectionunit 4.

At this time, as shown in FIG. 13, if the pressing device 10 presseswhile the test piece 1 is being held by the chuck 17, there is thepossibility that the test piece 1 will be pushed upon the detection unit4 in an orientation tilted against the chuck 17. Furthermore, as shownin FIG. 14, when the angle θ between the upper and side surfaces of thetest piece 1 is not a right angle, it is possible that the test piece 1could be brought into contact with the detection unit 4 with an unevenforce, or the detection unit 4 and the test piece 1 might not be broughtinto contact, or similar.

Even in these kinds of situations it is possible to identify the plastictypes contained in the test piece 1. However, as stated above, when thechuck opens and releases the test piece and the test piece becomesstationary before it is pressed by the pressing device, the test pieceand the detection unit can be better brought into contact. Therefore,identification of the plastic types contained in the test pieces can beperformed with greater accuracy and consistency. Note that although thedetection unit 4 shown in FIGS. 12 to 14 is the detection unit shown inFIG. 2 that uses an infrared total reflectance measurement method, thesame applies for detection units that use other methods.

In the plastic identifying method of the present invention, it is alsopossible to perform identification for at least two sides of the testpiece. Even in situations such as when surface coatings have beenapplied, or when there is surface degradation due to long use, theplastic types contained in the test pieces can be identified withgreater certainty when at least two surfaces of the test pieces sampledfrom the items to be identified are measured.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Theembodiments disclosed in this application are to be considered in allrespects as illustrative and not restrictive, the scope of the inventionbeing indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

INDUSTRIAL APPLICABILITY

With the plastic identifying apparatus or plastic identifying method ofthe present invention, the plastics contained in items to be identifiedcan be identified with good accuracy, and continuously, regardless ofthe size of the items to be identified.

1. A plastic identifying apparatus comprising: a sampling unit thatsamples a test piece from an item to be identified that containsplastic; an identifying unit provided with a detection unit thatidentifies a type of plastic contained in the test piece; and a supplyunit that supplies the test piece from the sampling unit to thedetection unit, wherein the supply unit comprises a chucking unit thatrotates the test piece sampled by the sampling unit while holding thetest piece so that at least two surfaces of the test piece arepositioned at the detection unit.
 2. The plastic identifying apparatusaccording to claim 1, wherein the detection unit irradiates infraredlight of a predetermined wave number onto the test piece, and detectsthe intensity of the infrared light that is totally reflected by thetest piece.
 3. The plastic identifying apparatus according to claim 1,further comprising a pressing device that brings the test piece intocontact with the detection unit.
 4. The plastic identifying apparatusaccording to claim 1, further comprising a cleaning unit that cleans thedetection unit.
 5. The plastic identifying apparatus according to claim1, wherein the sampling unit comprises a means for punching a test piecefrom the item to be identified.
 6. The plastic identifying apparatusaccording to claim 5, wherein the punching means is a punch press. 7.The plastic identifying apparatus according to claim 1, wherein thechucking unit comprises a rotation unit that rotates the test piecearound a horizontal rotational axis while the chucking unit holds thetest piece.
 8. The plastic identifying apparatus according to claim 1,wherein the shape of the test piece is an approximate “T” shape or anapproximate “L” shape.
 9. The plastic identifying apparatus according toclaim 1, wherein the chucking unit comprises a rotation unit thatarranges at least two sides of the test piece at the detection unit. 10.The plastic identifying apparatus according to claim 1, furthercomprising a cleaning unit that cleans a surface of the rest piece. 11.The plastic identifying apparatus according to claim 1, furthercomprising a pressing unit that presses against a surface of the testpiece.
 12. The plastic identifying apparatus according to claim 1,further comprising a polishing unit that provides a surface of the testpiece with uniformity.
 13. A plastic identifying method comprising: (i)a step of sampling a test piece from an item to be identified thatcontains plastic, (ii) a step of supplying the sampled test piece to adetection unit for identification of a type of plastic contained in thetest piece, and (iii) a step of identifying the type of plasticcontained in the test piece with the detection unit, wherein step (iii)is performed for at least two surfaces of the test piece by rotating thetest piece by using a chucking unit that is capable of rotating the testpiece so that the at least two surfaces are positioned at the detectionunit.
 14. The plastic identifying method according to claim 13, whereinstep (iii) includes a step of irradiating infrared light of apredetermined wave number onto the test piece, and detecting theintensity of the infrared light that is totally reflected by the testpiece.
 15. The plastic identifying method according to claim 13, whereinstep (iii) is performed by bringing the test piece into contact with thedetection unit.
 16. The plastic identifying method according to claim15, wherein step (iii) is performed by bringing the test piece intocontact with the detection unit after letting the test piece becomestationary above the detection unit.